Casement windows commonly have a window sash movably mounted in a frame using a system of links and pivot points. The window is opened as the sash pivots and translates within the frame. Many casement windows have a track mounted in the window frame on which runs a shoe assembly, connected with a sash arm, that guides the window sash during its travel from an open to a closed position. The track and shoe assembly guide the window sash in its translation. Casement windows often use pivots that are typically mounted, adjacent one end of the track, and formed to rotatably retain a swivel arm on one end. The swivel arm is further rotatably interconnected, on a second end, to a sash arm by a pivot. The pivots and arm links control the rotation of the window sash.
The hinge, as a whole, maintains the relationship of the sash to the window frame. For the casement window to close and seal effectively, proper positioning of the hinge pivots must be maintained. When one or more of the hinge pivots are not properly positioned, the window sash is misaligned with respect to the window frame. Over the life of the window, effective closure and sealing may be impaired by shifting of the window frame or the window sash and wear in the linkages. This misalignment of the window sash with the window frame is commonly referred to as "sash sag".
"Sash sag" can be corrected by the slight repositioning of a pivot. This repositioning has been accomplished in the past by using a slotted hole on a track assembly. A pivot, for the swivel arm, is secured to the track assembly by a screw that engages the slotted hole. When "sash sag" occurs, the screw is loosened and the pivot is moved to a new location, thereby reducing the "sash sag". Repeated adjustment of the hinges tends to put substantial wear on the pivot mount and the pivot mounting hardware, thereby reducing the useable life of the hardware. Also, repeated loosening and tightening of the screws has shown to be cumbersome when making small adjustments.
More recently, eccentric shaped adjustable pivots have been used to provide for adjustment of a casement window hinge to reduce "sash sag" or correct any other alignment problems. Eccentric shaped adjustable pivots of this type typically include a stud, having a flange with surfaces for engaging an adjustment tool, having a pivot portion, about which the swivel arm pivots, and an eccentric neck, frictionally secured to the window frame or the track, about which the pivot axis rotates when the alignment is adjusted. A window hinge of this type is shown in U.S. Pat. No. 5,307,539 issued to Bauman. The Bauman patent discloses a stud which requires a wrench engaging a flange for making alignment adjustments. Having this tool engagement site makes it necessary for an adjuster to engage the wrench roughly perpendicular to the hinge axis. Because of the tight spaces associated with casement window hardware, this may not be convenient.
Other known hinge pivots require disassembling the track assembly in order to adjust the pivot position to correct "sash sag". In this design, discrete hinge pivot positions are indexed by engagement of an index cam with a cam-engaging element. The index cam is further interconnected with a link engaging pivot. The cam-engaging element may be a part of the track assembly. When readjustment of the link engaging pivot is desired, the track must be disassembled, the index cam must be reoriented with respect to the cam-engaging element, and the track must then be reassembled. U.S. Pat. No. Re. 34,657 issued to La See suggests an adjustable pivot of this type.
Accordingly, it would be advantageous to provide a hinge that is not required to be in one of a limited number of discrete positions and which is easily adjustable. It would also be advantageous to provide an adjustable pivot having a tool access position in which the tool is engageable, with the adjustment stud, roughly parallel to the pivot axis, providing simplified access to the adjustment stud because the tool access region is located at the exposed end of the post. It would further be advantageous to provide an adjustable pivot having an indicator that helps to visually indicate the rotational position of the stud. For example, the indicator may be a flat side of a partially circular flange. It would further be advantageous to provide an adjustment stud having a tenon mounted in the track assembly using a frictional fit or an interference fit. This allows the adjustment stud to be rotated 360 degrees and set at any position therein. Using a frictional fit also provides for a simplified and cost effective assembly whereby the tenon is simply press fit into an aperture in the track assembly. It would further be advantageous to provide an adjustment stud that may be manufactured to improve performance and cost either as a single-member stud or as a multi-member stud, depending on the needs of the application. Manufacturing a multi-member stud allows a designer to choose different materials to be used for manufacturing the different members, depending on the desired performance characteristics. For example the tenon could be made from a different material than the post or the tool access region. It would further be advantageous to provide an adjustment stud that can easily eliminate "sash sag" through a simple adjustment to the adjustment stud.